Self healing lead wires in humid environments
A device is provided that may be operated when implanted within a body, when mounted to a surface of an eye, or when immersed in a fluid or otherwise exposed to a humid environment. The device includes at least one conductor that includes a valve metal. The valve metal is disposed on an external surface of the conductor such that, when the conductor exhibits a positive voltage relative to its environment, the valve metal forms or maintains a self-limiting oxide layer. The device is operated such that the mean voltage of the conductor is positive or zero relative to the environment, e.g., relative to another electrode or other conductor of the device that is in contact with fluid in the environment. Such a device can be operated for a protracted period of time in a humid environment without a hermetic seal disposed between the conductor and the humid environment.
1. A device that is immersible in a body fluid, the device comprising:
a first conductor, wherein a surface of the first conductor comprises a valve metal;
a second conductor;
an electrical component that is electrically coupled to the first conductor and the second conductor, wherein the electrical component comprises a sensor, and wherein the sensor comprises a first electrode and a second electrode; and
a controller, wherein the controller is electrically coupled to the electrical component via the first conductor and the second conductor, wherein the controller is electrically coupled to the first electrode via the first conductor, wherein the controller is electrically coupled to the second electrode via the second conductor, and wherein the controller is operable to apply a voltage between the first conductor and the second conductor such that the first conductor has a positive voltage relative to the second conductor.
2. The device of claim 1 , further comprising a polymeric material, wherein the first conductor, second conductor, electrical component, and controller are at least partially embedded within the polymeric material, wherein the polymeric material is permeable to water, and wherein the polymeric material is shaped to be mounted on an external surface of an eye.
3. The device of claim 1 , wherein the electrical component comprises an adjustable lens, wherein an optical power of the adjustable lens is related to a magnitude of at least one of a voltage or a current applied to the adjustable lens by the controller via the first conductor and the second conductor.
4. The device of claim 1 , wherein the valve metal comprises at least one of aluminum, tungsten, titanium, vanadium, zirconium, niobium, hafnium, molybdenum, or tantalum.
5. The device of claim 1 , wherein the device further comprises:
a barrier layer, wherein the first conductor is enclosed within the barrier layer such that the barrier layer impedes negative ions from an environment of the device from interacting with the first conductor.
6. The device of claim 5 , wherein the barrier layer impedes chloride ions from an environment of the device from interacting with the first conductor.
7. The device of claim 6 , wherein the barrier layer comprises a layer of parylene.
8. The device of claim 7 , wherein the layer of parylene has a thickness greater than 1.5 microns.
9. The device of claim 5 , wherein the barrier layer comprises a substance that getters chloride ions.
10. The device of claim 5 , wherein the barrier layer comprises a substance that getters hydroxide ions.
11. The device of claim 1 , wherein the surface of the first conductor further comprises an oxide layer, wherein the oxide layer comprises an amount of the valve metal that is oxidized.
12. The device of claim 1 , wherein a surface of the second conductor comprises a noble metal.
13. A device that is immersible in a body fluid, the device comprising:
a first conductor, wherein a surface of the first conductor comprises a valve metal;
a second conductor, wherein a surface of the second conductor comprises a valve metal;
an electrical component that is electrically coupled to the first conductor and the second conductor; and
a controller, wherein the controller is electrically coupled to the electrical component via the first conductor and the second conductor, and wherein the controller is operable to:
apply, during a first period of time, a voltage between the first conductor and the second conductor such that the first conductor has a positive voltage relative to the second conductor; and
apply, during a second period of time, a voltage between the first conductor and the second conductor such that the first conductor has a negative voltage relative to the second conductor.
14. The device of claim 13 , further comprising a polymeric material, wherein the first conductor, second conductor, electrical component, and controller are at least partially embedded within the polymeric material, wherein the polymeric material is permeable to water, and wherein the polymeric material is shaped to be mounted on an external surface of an eye.
15. The device of claim 13 , wherein the electrical component comprises an adjustable lens, wherein an optical power of the adjustable lens is related to a magnitude of at least one of a voltage or a current applied to the adjustable lens by the controller via the first conductor and the second conductor.
16. The device of claim 13 , wherein the electrical component comprises a sensor, wherein the sensor comprises a first electrode and a second electrode, wherein the controller is electrically coupled to the first electrode via the first conductor, and wherein the controller is electrically coupled to the second electrode via the second conductor.
17. The device of claim 13 , wherein the valve metal comprises titanium.
18. The device of claim 17 , wherein the surface of the first conductor further comprises an oxide layer, wherein the oxide layer comprises titanium oxide.
19. The device of claim 13 , wherein the device further comprises:
a barrier layer, wherein the first conductor and second conductor are enclosed within the barrier layer such that the barrier layer impedes negative ions from an environment of the device from interacting with the first conductor and second conductor.
20. The device of claim 13 , wherein the device further comprises:
a barrier layer, wherein the first conductor and second conductor are enclosed within the barrier layer such that the barrier layer impedes negative ions from an environment of the device from interacting with the first conductor and second conductor, and wherein the barrier layer comprises a substance that getters chloride ions.